1. Field
Exemplary embodiments of the present inventive concept relate generally to thin film transistors. More particularly, exemplary embodiments relate to thin film transistor substrates that may be used for display devices, and methods of their manufacture.
2. Description of the Related Art
Generally, a thin film transistor for driving a pixel unit in a display device includes a gate electrode, a source electrode, a drain electrode, and an active pattern forming a channel between the source electrode and the drain electrode. The active pattern includes a semiconductor layer including amorphous silicon, polycrystalline silicon, an oxide semiconductor, or the like.
Amorphous silicon has a relatively low electron mobility, which may be about 1 to about 10 cm2N, so that an amorphous silicon thin film transistor has relatively low driving characteristics. In contrast, polycrystalline silicon has a relatively high electron mobility, which may be about 10 to about hundreds of cm2/V. However, a crystallization process is required for forming polycrystalline silicon. Thus, it is difficult to form a uniform polycrystalline silicon layer on a large-sized substrate, and resulting manufacturing costs are high. Oxide semiconductors may be formed through a low-temperature process that is relatively easily scaled up, and have a high electron mobility. Thus, research is actively being conducted on thin film transistors which include an oxide semiconductor.
However, when a passivation layer is formed using plasma treating, ionized atoms may impact the oxide semiconductors. This may generate defects within the oxide semiconductors. This in turn may manifest as defects in the display apparatus.